The invention relates to a method for producing hydrolysates from protein-containing plant and animal raw materials.
Protein-containing plant and animal natural and waste products can be prepared in a variety of ways for material application. As a rule it is accordingly necessary to split the macromolecules (proteins) both into amino acids and also peptides, comprising several amino acids.
Protein-hydrolysis is known which leads to an amino acid mixture through addition of acids or bases with temperature effect. After the protein is split the solution must be neutralised, though the important and economically interesting amino acid tryptophan is destroyed during acid hydrolysis.
The protein splitting can also be carried out enzymatically using proteases of microbial origin. At the same time both endopeptidases, which break up peptide chains into different fragments according to their splitting specificity, and exopeptidases, which provide amino acids, are used.
Methods and processes of pH value-dependent and enzymatic protein hydrolysis are described inter alia in GB 846682, RU 2132142 and U.S. Pat. No. 6,221,423.
Macromolecules of complex materials of animal and plant waste, such as carbohydrates, fats and proteins, can also be split under the effect of raised pressure and raised temperature. The resulting fragments are made available to microbially supported energetic application, e.g. methane development.
In U.S. Pat. No. 6,365,047, ES 2162462T and DE 10117321 the prior art of pressure temperature hydrolysis is illustrated with respect to the procedural solutions.
DE 10113537 describes the pressure-temperature treatment for animal meal. In the basic medium a pressure of 2.5 bar and a temperature of 150° C. at least 15 min have an effect on the aqueous animal meal suspension, predominantly in terms of inactivation of the BSE exciter of infected animal meal and flesh pulp.
According to EP 1406508 BSE-free animal meal is split by total hydrolysis of the protein of the animal meal into amino acids with addition of acids/lyes and if required subsequent processing with proteases. Neutralisation must follow the splitting process.
All these methods are, however, not suitable for making hydrolysates in defined molecular weight limits.